The present invention relates to fuel injectors and more particularly to a solenoid actuated fuel injector.
Prior known techniques in the design and manufacture of fuel injectors have been complex and cumbersome. The fuel injector valve body would typically be flipped a series of times before fabrication is completed. Additionally, the number of parts in the injector assembly, and in particular, the number of parts in the valve group affects several parameters including the material costs, the number of rotating work stations required to assemble the injector, and the speed at which the assembly can be fabricated. Further, the number of welds in an injector assembly also affects the equipment required to manufacture the injector, and the rate at which the injector can be assembled.
It would be beneficial to provide a fuel injector wherein the number of total parts comprising the fuel injector assembly is reduced, the assembly procedure requires no flipping of the valve body, and the number of rotating work stations along with the total number of total welds required to fabricate the injector is reduced.
Briefly, the present invention provides a solenoid actuated fuel injector. The solenoid actuated fuel injector comprises a valve group including a valve body having an upstream end, a downstream end and a longitudinal axis extending therethrough. The valve group additionally includes an inlet tube having an upstream end, a downstream end, and an inlet tube channel. The downstream end of the inlet tube is connected to the upstream end of the valve body. The inlet tube also includes at least one formed slot. The valve group further includes an armature/ball assembly reciprocally disposed in the valve body along the longitudinal axis. In addition, the downstream end of the inlet tube is spaced a predetermined distance from the upstream end of the armature/ball assembly.
The solenoid actuated fuel injector is further comprised of a power group including a coil assembly that cinctures the inlet tube, a housing that encases the coil assembly, and an overmold that encapsulates the housing and coil assembly. The overmold includes at least one overmold slot that is formed in the overmold. The power group is additionally comprised of a retainer that extends through the at least one overmold slot and the at least one inlet tube slot, the retainer retains the power group to the valve group.
The present invention also provides a further embodiment of a solenoid actuated fuel injector. The fuel injector comprises a valve body having an upstream end, a downstream end and a longitudinal axis extending therethrough. The embodiment additionally comprises an armature/ball assembly reciprocally disposed in the valve body along the longitudinal axis, and an inlet tube having an upstream end, a downstream end, and an inlet tube channel. The embodiment further includes a downstream end of the inlet being tube contiguous to the upstream end of the valve body, and a downstream end of the inlet tube being spaced a predetermined distance from the upstream end of the armature/ball assembly.
The present invention also provides a method of manufacturing a solenoid actuated fuel injector. The method comprises welding an upper surface of a ball seat to a lower surface of a lower guide, the welded surface of the ball seat to the lower surface of the lower guide providing a hermetic seal. The method includes loading an orifice disk, ball seat and lower guide into a downstream end of a valve body, welding the valve body to the ball seat, thus retaining the orifice disk, ball seat and lower guide in place in the downstream end of the valve body. The method further includes welding a ball to a downstream end of an armature stem forming an armature/ball assembly, and loading the armature/ball assembly through an upstream end of the valve body.
The method of manufacturing a solenoid actuated fuel injector additionally comprises pressing an inlet tube into the valve body a predetermined distance, welding the inlet tube to the valve body, thus securing the inlet tube to the valve body. The method includes pressing a power group comprised of a housing and coil subassembly onto the inlet tube, retaining the power group to the inlet tube by sliding a retainer through slots aligned in the power group and slots formed in the inlet tube. The method further includes installing first a spring, and second an adjusting tube a predetermined distance into a top end of the inlet tube, securing the adjusting tube in place after completing the installation. A combination retainer/fuel filter is pressed in an upstream end of the inlet tube, completing the assembly.
The present invention further provides a method of operating a solenoid actuated fuel injector comprising energizing a coil, generating an electromagnetic flux that flows from the coil to an inlet tube, from the inlet tube to a coil housing, from the coil housing to a valve body, from the valve body across a side air gap to an armature/ball assembly, from the armature/ball assembly across a working air gap back to the inlet tube. The method of operating the solenoid actuated fuel injector further includes displacing the armature/ball assembly a predetermined lift distance.
An alternate embodiment of the present invention provides a solenoid actuated fuel injector. The solenoid actuated fuel injector comprises a valve group including a valve body having an upstream end, a downstream end and a longitudinal axis extending therethrough. The valve group additionally includes an inlet tube having an upstream end, a downstream end, and an inlet tube channel. The downstream end of the inlet tube is connected to the upstream end of the valve body. The inlet tube also includes at least one formed slot. The valve group further includes an armature/ball assembly reciprocally disposed in the valve body along the longitudinal axis. In addition, the downstream end of the inlet tube is spaced a predetermined distance from the upstream end of the armature/ball assembly.
The alternate embodiment of the solenoid actuated fuel injector is further comprised of a power group including a coil assembly that cinctures the inlet tube and an overmold that encapsulates the coil assembly. The overmold includes at least one overmold slot that is formed in the overmold. The power group is additionally comprised of a retainer that extends through the at least one overmold slot and the at least one inlet tube slot, the retainer retains the power group to the valve group.
The alternate embodiment of present invention also provides a method of manufacturing a solenoid actuated fuel injector. The method comprises welding an upper surface of a ball seat to a lower surface of a lower guide, the welded surface of the ball seat to the lower surface of the lower guide providing a hermetic seal. The method includes loading an orifice disk, ball seat and lower guide into a downstream end of a valve body, welding the valve body to the ball seat, thus retaining the orifice disk, ball seat and lower guide in place in the downstream end of the valve body. The method further includes welding a ball to a downstream end of an armature stem forming an armature/ball assembly, and loading the armature/ball assembly through an upstream end of the valve body.
The method of manufacturing the alternate embodiment of the solenoid actuated fuel injector additionally comprises pressing an inlet tube into the valve body a predetermined distance, welding the inlet tube to the valve body, thus securing the inlet tube to the valve body. The method includes pressing a power group comprised of an overmolded coil subassembly onto the inlet tube, retaining the power group to the inlet tube by sliding a retainer through slots aligned in the power group and slots formed in the inlet tube. The method further includes installing first a spring, and second an adjusting tube a predetermined distance into a top end of the inlet tube, securing the adjusting tube in place after completing the installation. A combination retainer/fuel filter is pressed in an upstream end of the inlet tube, completing the assembly.
The alternate embodiment of the present invention further provides a method of operating a solenoid actuated fuel injector comprising energizing a coil, generating an electromagnetic flux that flows from the coil to an inlet tube, from the inlet tube across a coil air gap to a valve body, from the valve body across a side air gap to an armature/ball assembly, from the armature/ball assembly across a working air gap back to the inlet tube. The method of operating the solenoid actuated fuel injector further includes displacing the armature/ball assembly a predetermined lift distance.